The present application is based upon and claims priority to Japanese Application No. 11-304647, filed Oct. 26, 1999.
1. Field of the Invention
The invention relates to a charging system for a small boat and more particularly to a charging system for a small boat employing a plurality of motors.
2. Description of the Related Art
Marine drives often employ an internal combustion engine to power a propulsion unit of the drive system. It is well known that internal combustion engines rely heavily on electric components, including fuel injector solenoids, ignition system, control system and the like. To power these engine components, most engines include an engine driven generator (e.g., an alternator) to produce electricity. The generator is utilized to charge a storage battery, and the battery in turn powers the electrical components. This approach provides a stable supply of voltage to the electrical components.
In some boats, the generator also charges a second battery that powers various accessories on the boat (e.g., lights, gauges, etc.). A typical arrangement of this charging system is illustrated in FIGS. 1 and 2.
FIG. 1 is a perspective view of a boat 10 that employs a pair of outboard motors 12, 14 mounted on the transom of the boat. A motor battery 16, 18 is associated with each outboard motor 12, 14 and is connected to a starter motor 20, 22 of the outboard motor 12, 14. Each alternator 24, 26 charges the corresponding motor battery 16, 18, and the alternator 24 of the port side motor 12 also charges an accessory battery 28. The accessory battery powers various accessories of the boat, such as lights 29, gauges 27, radios, navigational equipment and the like.
FIG. 2 is a circuit diagram of a conventional charging system for the boat shown in FIG. 1. The three-phase alternator 24 of the port side outboard motor 12 (the xe2x80x9cleft enginexe2x80x9d) is connected to one terminal of the motor battery 16 through a first three-phase rectifier, and is connected to one terminal of the accessory battery 28 through a second three-phase rectifier. The first rectifier is formed by a first set of diodes 30 and a second set of diodes 32. The second rectifier is formed by a third set of diodes 34 and the second set of diodes 32. The anodes of the second set of diodes 32 are grounded as are the other terminals of the motor and accessory batteries 16, 28.
The alternator 24 is also connected to a regulator 36. The regulator 36 includes three thyristors. The gates of the thyristors are connected to a controller 38 having a microprocessor. The controller 38 sends trigger signals to the gates to control the firing of the thyristors. The input terminal a of the controller 38 is connected to the alternator 24 via another three-phase rectifier 40. When a voltage at the input terminal becomes higher than a desired voltage, for example, 15.5 volts, the controller 38 sends trigger signals to the thyristors, which, in turn, connect the output of the alternator 24 to the ground 42.
The alternator 26 of the starboard side outboard motor (the xe2x80x9cright enginexe2x80x9d) is not connected to the accessory battery 28 and thus does not charge the accessory battery 28. For this reason, the charging circuitry associated with the right engine alternator 26 does not include a three-phase rectifier disposed between the alternator and the accessory battery, as the rectifier 34 does with in the charging circuitry associated with the left engine alternator 24. Except for these differences, the charging circuitry associated with the alternators 24, 26 are the same.
In some operating conditions, the left engine battery 16 is fully charged, but the accessory battery 28 and the right engine battery 18 are not. Prior charging systems cannot take advantage of continuing charging of the right engine battery 18 by the right engine alternator 26 to charge the accessory battery. In other situations, where only the right engine is running, the accessory battery will not be charged.
The present charging system allows for at least one battery of a vehicle""s (e.g., a watercraft""s) electrical system to be powered by multiple generators without the risk of overcharging that battery or any other batteries that are simultaneously charged by the generators. It is understood, however, that various aspect and features of the present charging system can also be employed in the situation where only one generator charges two or more batteries. The following summarizes some of the aspects and features of the present charging system and its method of operation.
One aspect of the invention involves a charging system for a watercraft having at least one marine drive that includes an engine. The charging system charges at least first and second batteries. The first battery is associated with the marine drive and the second battery is arranged to power accessories on the watercraft. A power generator of the charging system is driven by the engine and selectively charges the first and second batteries. A regulator is coupled to the generator to regulate the voltage supplied to the first and second batteries. The charging system also includes at least one controller that is connected to the first battery to determine a voltage at the first battery, to the second battery to determine a voltage at the second battery, and to the regulator for controlling the regulator. The controller is configured to compare the determined voltages of the first and second batteries with a predetermined overcharged voltage and to regulate the voltage supplied by the generator when the voltage at one of the first and second batteries is greater than the overcharged voltage.
In one preferred mode, the controller is further configured to compare the determined voltages of the first and second batteries with a predetermined fully charged voltage. The controller operates the regulator so as not to regulate the voltage supplied by the generator when the voltage at one of the first and second batteries is less than the fully charged voltage, even though the voltage at the other battery is greater than the fully charged voltage (but less than the overcharged voltage).
Another aspect of the invention involves a charging system for a watercraft having at least one marine drive that includes an engine. The charging system charges at least first and second batteries. The first battery is associated with the marine drive and the second battery is arranged to power accessories on the watercraft. A power generator of the charging system is driven by the engine and selectively charges the first and second batteries. A regulator is coupled to the generator to regulate the voltage supplied to the first and second batteries. The charging system also includes at least one controller that is connected to the first battery to determine a voltage at the first battery, to the second battery to determine a voltage at the second battery, and to the regulator for controlling the regulator. The controller is configured to compare the determined voltages of the first and second batteries with a predetermined fully charged voltage. The controller operates the regulator so as not to regulate the voltage supplied by the generator when the voltage at one of the first and second batteries is less than the fully charged voltage.
In a preferred mode, the controller is further configured to compare the determined voltages of the first and second batteries with a predetermined undercharged voltage. The controller operates the regulator so as to regulate the voltage supplied by the generator when the voltage at one of the batteries is greater than the fully charged voltage and one of the voltage at the other battery is greater than the undercharged voltage.
In a further preferred mode, the controller compares the determined voltages of the first and second batteries with a predetermined overcharged voltage. If the voltage at one of the batteries is greater than the overcharged voltage, the controller regulates the voltage supplied by the generator even though the voltage at the other battery is not greater than the undercharged voltage.
In a preferred form, the regulator, in the modes of the charging system summarized above, is configured generally to suspend the supply of electrical power to each battery.
In accordance with another aspect of the present invention, a watercraft includes a charging system and at least one marine drive that includes an engine. The charging system charges at least first and second batteries of the watercraft. The first battery is associated with the marine drive and the second battery is arranged to power accessories on the watercraft. A power generator of the charging system is driven by the engine and selectively charges the first and second batteries. A regulator is coupled to the generator to regulate the voltage supplied to the first and second batteries. The charging system also includes at least one controller that is connected to the first battery to determine a voltage at the first battery, to the second battery to determine a voltage at the second battery, and to the regulator for controlling the regulator. The controller is configured to compare the determined voltages of the first and second batteries with a predetermined fully charged voltage, with an overcharged voltage and with an undercharged voltage. The controller is configured to operate the regulator so as to suspend power supply from the alternator to the batteries (1) when the voltages at both batteries are greater than the undercharged voltage and the voltage of at least one of the batteries is greater than the fully charged voltage, or (2) when the voltage of at least one of the batteries is not greater than the undercharged voltage and the voltage of the other battery is greater than the overcharged voltage. The controller also is configured to operate the regulator so as not to regulate and permit power to be supplied from the alternator to the batteries (1) when the voltages of both batteries are lower than the fully charged voltage, or (2) when the voltage at one of the batteries is between the fully charged voltage and the overcharged voltage and the voltage of the other battery is not greater than the undercharged voltage.
Yet another aspect of the invention involves a method of charging batteries of a charging device for a watercraft having at least one marine drive, wherein the batteries comprise a first battery associated with the motor and a second battery associated with accessories on the watercraft. The method comprises determining whether the voltages are higher than the fully charged voltage, and whether at least one of the voltages at the first battery and the second battery becomes higher than the overcharged voltage; if so, allowing the controller to operate the regulator so that supplying electric power to each of the batteries from the generator can be suspended; detecting voltages at the first battery and the second battery to decide whether at least one of the voltages at the first battery and the second battery becomes lower than the fully charged voltage, and whether both of the voltages at the first battery and the second battery become lower than the overcharged voltage; if so, allowing the controller to output a signal to suspend the regulator so that electric power to each of the batteries from the generator can be supplied.
Another aspect of the invention involves a method for charging batteries of a watercraft. At least one of the batteries is associated with an engine of the watercraft and the at least another battery is associated with at least one accessory on the watercraft. The batteries are charged by at least one power generator driven by the engine. The method involves determining the voltage at each of the batteries and comparing the voltage at each of the batteries with a predetermined overcharged voltage. If one of the voltages at the batteries is greater than the overcharged voltage, then the voltage supplied by the generator to the batteries is regulated.
In accordance with an additional aspect of the invention, a method for charging batteries of a watercraft involves determining the voltage at each of the batteries and comparing the voltage at each of the batteries with a predetermined fully charged voltage. The voltage at each of the batteries also is compared with a predetermined undercharged voltage. If the voltage at one of the batteries is greater than the fully charged voltage and the voltage at the other battery is not less than the undercharged voltage, then the voltage supplied by the generator to the batteries is regulated. If both of the voltages at the batteries are not greater than the fully charged voltage, then the voltage supplied by the generator is not regulated.
Further aspects, features and advantages of this invention will become apparent from the detailed description of the preferred embodiment which follows.